A tray sealer is known from DE 10 2008 030 510 A1, in which a gripper system grips trays which were positioned on a feeding belt by means of two horizontally movable grippers. The grippers transport the trays into a sealing station in which they are sealed with a top film. After the sealing procedure, the sealed trays are transported out of the sealing station by the two grippers and transferred onto a discharge belt. The grippers simultaneously transport both the unsealed trays into the sealing station as well as the sealed trays out of the sealing station. Such a gripper system requires a large amount of space for the gripper movements that occur outside and in particular at the side of the sealing station, as well as for driving and guiding means of the gripper system. Prerequisite for the use of gripper systems is, that the trays are respectively grouped and position at a distance from the grippers on a feeding belt, after being fed to the feeding belt of the sealing machine at an irregular or non-matching distance. Such a gripper system cannot be used for an at least three-lane tray sealer.